A police spokesman said: “A 47-year-old man was injured when he was surrounded by a group of youths and attacked outside during the incident.

“Four people were subsequently identified and arrested, but following extensive enquiries it was not possible to establish who had caused the injury and no charges were brought in relation to this incident.”

Police confirmed they had considered ‘joint enterprise’ – a law which has been used to convict people, usually in gang-related cases, if defendants ‘could have foreseen’ violent acts by their associates – but said it could not be proven in this case.

The spokesman said: “The incident took place away from the shop after the initial shoplifting.

“There were a number of youths at the location, but most did nothing and it was not possible to ascertain who was involved and who wasn’t.

“The victim was not able to provide identification evidence, the CCTV did not help and there was no witness evidence that assisted the case.

“Therefore, we were unable to prove who within the group was involved in the assault and as a result joint enterprise cannot be proven.”

A 15-year-old boy from Southwick pleaded guilty to theft from a shop in relation to the incident, police said.

He was referred to the Youth Offender Panel for a six-month contract, made the subject of a restraining order and ordered to pay £20 compensation, police confirmed.

A spokesman for the Crown Prosecution Service confirmed that the only charge that was referred to the CPS related to the theft from the shop.